An electric wire such as a shield wire is composed mainly of a core wire, an insulating layer (internal coating layer) which coats the periphery thereof, a shield layer (braid) which coats the periphery of the insulating layer, and a protective coating layer which coats the periphery of the shield layer. When this electric wire is connected to various electric apparatuses and the like for use, it is necessary to cut and pull out the protective coating layer and shield layer for removal thereof. However, while cutting and pulling out the protective coating and shield layers, the core and insulating layers are often damaged, which ultimately results in additional problems such as change in electric properties of the electric wire.
Generally the outermost protective coating layer is cut with a cutting machine and pulled out, and then a thin plate-like insertion member is inserted between the shield layer and the insulating layer thus displacing the shield layer from the insulating layer. Then, the floating shield layer (i.e., the displaced shield layer) is cut with a cutting machine along the insertion member. Thus, preventing or reducing damage to the insulating layer associated by cutting.
However, the above described process requires a complex and troublesome step of inserting the inserting member between the closely-adhered shield layer and the insulating layer for cutting.
On the other hand, a process for producing a shield layer-cut electric wire of Patent Document 1 shown in FIG. 7 is known as another process for easily cutting a shield layer. In this process, a shield diameter expanding means compresses a shield wire 400 in an axial direction from both sides of an exposed portion of the shield layer 430 so that the shield layer 430 swells, as shown in FIG. 7 (a). Then, a space is created between the shield layer 430 and an internal coating layer (insulating layer) 420, as in an E-E cross section shown in FIG. 7 (b). In that state, laser light is applied in a tangential direction of the cross section of the shield layer 430, and goes around an outer periphery of the shield layer 430, thereby making it possible to cut the shield layer 430 alone without damaging the internal coating layer 420.
However, in this process, the laser light must be precisely controlled to prevent laser light application to the internal coating layer 420. Also, the space between the shield layer 430 and the internal coating layer 420 must be set at such a level that laser light and radiation heat would not influence or affect the internal coating layer 420. Further, when the type of shield wire has been changed, if the laser is not accurately reset, the laser light may be applied to the internal coating layer 420, thereby damaging the internal coating layer 420.